Safety device for circuit controllers



Dec. 2, 1958 c. H. HOPKINS ETAL 2,863,012

- SAFETY DEVICE FOR CIRCUIT CONTROLLERS Filed March 5, 1958 2 Sheets-Sheet 1 CONTROLS 56/ I: l a 37 i/3Z o r-: I 2%; fl/ --4a CHARLES H. HOPKINS Z HUGH MATH/5 W9 3 33 33 INVENTORS BY r 30 3o-0 C. H. HOPKINS ET AL SAFETY DEVICE FOR CIRCUIT CONTROLLERS Dec. 2 1958 2 Sheets-Sheet 2 Filed March 5, 1958 CHARL5 H HOPKINS HUGH MATH/s JNVENTORS W67 fifty.

United States SAFETY DEVICE FOR CmCUIT CONTROLLERS Charles H. Hopkinsand Hugh Mathis, Cincinnati, Ohio Application March 5, 1958 Serial No. 719,327

12 Claims. (Cl. 200-50) trols for numerous motors and other electrical devices of an entire factory or other commercial establishment. In many cases, the controllers pass electric currents of dangerously high voltage or amperage, so that for reasons of safety, no unauthorized or uninformed person gaining admittance to the control room should be enabled to close the circuit of a controller found in the open-circuit condition. Where such unauthorized manipulation was possible in the past, there was present the constant danger of subjecting electrical repairmen or equipment installers working with such circuits, to great bodily injury or perhaps the loss of life.

An object of the present invention is to provide improved and conveniently operative safety lock means for application to circuit controllers of the type above mentioned.

Another object is to provide safety locking means for the purposes stated, which with great facility and dispatch may be applied very economically to existing circuit controllers as well as .to new controllers in the process of manufacture.

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A further object of the invention is to provide simple position, once the lever has been moved to that position either manually, or automatically by the action of a circuit breaker Within the controller cabinet.

The foregoing and other objects are attained by the means described herein and illustrated upon the accompanying drawings, in which:

Fig. l is a front elevational view of a circuit controller in the form of a door-equipped cabinet, and incorporating the safety means of the present invention.

Fig. 2 is a view similar to Fig. 1 showing the interior of the cabinet, the door being removed for convenience of disclosure.

Fig. 3 is a rear elevational view of the cabinet door, showing means for actuating a circuit-breaker and associated means for latching the cabinet door and locking the actuating lever thereof.

Fig. 4 is a perspective view of a door latch forming a detail of the structure.

Fig. 5 is an elevational view similar to Fig. 3, showing the means of the invention in operative position.

Fig. 6 is a detail view showing in side elevation a socket unit forming part of the structure.

Fig. 7 is a side elevational view of a key-returned spring-bolt lock which may be utilized in the combination embodying the invention.

Fig. 8 is an elevational view of a guide stud forming a detail of the invention.

Patentecl Dec. 2, 1958 Referring to the accompanying drawings, Fig.- 1 illustrates in front elevation a cabinet to which access may be had byway of a door 9, the door being preferably hinged to the cabinet at 1010 for swinging movement to open and .closed positions. Accessible exteriorly of the door is an actuating lever 12 which [may be swung in a vertical plane to any of the three positions indicated as On, Trip, or Off. The cabinet door is latched in closed position whenever the lever 12 is in the On or Trip positions, or any intermediate position, but when moved to the Off position the lever releases the latch to permit opening the door, as will be more fully explained hereinafter.

With the door 9 swung open as in Fig. 2, access may be had to a circuit breaker 13 and its actuating element 14, which latter may be in the form of a lever shiftable within the limits of a vertical slot 15 to open and close the circuit of the breaker. In the example shown, .the actuating element 14 is in the On or closed circuit position. To break the circuit it is necessary to move the element 14 to a position at the lower end of slot 15.

Circuit breaker 13 may have the usual electrical connections with a motor starter or other control device indicated generally by the character 16. Various other elements may be housed within the cabinet, such as for example the terminal block 17, a box 18 containing relays and other control equipment, and the like. Such equipment may be mounted upon a panel 19 fitted into the cabinet and rendered bodily displaceable by means of handles 21. The cabinet is indicated generally by the character .20, and may be in the form of a rectangular box having side, top, and bottom walls 22, 23, 24 and 25. Side wall 22 may carry an inwardly extending keeper 26, which as will be explained, is engageable by a latch on door 9 to hold the door in closed position. The latch is indicated at 27 in the several drawing views.

Referring now to Figs. 3 and 5, the door 9 carries upon its rear or inner face the mechanism necessary for selectively latching the door, shifting the circuit breaker actuator 14, and locking the shift mechanism against unauthorized disposition to the On or closedcircuit condition. The character 29 indicates a fiat mounting plate screwed, bolted, or otherwise attached to the rear of the door at locations 30, this plate being apertured to receive stud 37 of disconnect handle or lever 12 which projects through a registering opening in the cabinet door. Mounting plate 29 carries guide means for a shifter plate 31 which, by means of handle 12, is movable in a vertical plane relative to mounting plate 29. The guide means 33 may be of any suitable type or construction, herein shown by way of example as a series of studs or stools annularly grooved at 32, Fig. 8, to slidingly accommodate the side edges of plate 31. The stools not only guide the shifter plate 31 for reciprocation, but serve also to space the shifter plate from the mounting plate 29, so as to provide space .therebetween for accommodating an operating cam and the latch 27, as will be explained.

One of the stools or studs 33 may provide an anchorage for one end 34 of a tension spring 35, the opposite end 36 of which is anchored to shifter plate 29 as shown, to constantly urge the shifter plate toward the elevated position of Fig. 3. Reciprocation of the shifter plate 29 is effected by the hand lever 12, between upper and lower limits according to the following described mechanism.

The inner or free end of the lever stud or pivot 37 has fixed thereto an operating cam 40 in parallelism with mounting plate 29, said cam carrying an extending pin 41 adapted to ride in a transverse slot 42 formed in an edge 43 of shifter plate 31. As cam 40 is rotated counter- 2,sea,012 r clockwise (Fig. 3), the pin 41 will move therewith to depress plate 31 to the lowered position of Fig. 5. Rotation of the cam in the opposite direction elevates the plate 31 to the extent permitted by a step 45 on the cam striking a stationary abutment 46 fixed upon the mounting plate or base 29. In this position of the cam and shifter plate 31, the disconnect handle or lever 12 is disposed to the On position. When the shifter plate is fully lowered according to Fig. 5, the handle or lever 12 will assume the Off or lowered position.

It may here be noted that latch member 27 lies flatwise against the mounting plate 29, and is pivoted thereto by means of a screw 47 the head of which is exposed exteriorly of the cabinet door, Fig. 1. Where the screw attaches to the latch member the connection is fixed, so that by means of a screwdriver applied exteriorly of the door, the latch yrnay be manually lifted to release the door for opening about its hinges 10. The body of the latch member rests between the cam 40 and the mounting plate 29, and may be provided with an elongate center opening 48 through which the handle pivot 37 freely extends so as not to interfere with rocking movements of the latch member. The latch member in lowered position engages the keeper 26, Fig. 2, to hold the door in closed position. By elevating the latch member, it clears the keeper and permits the door to be swung open.

Reverting to Fig. 5, it is noted that latch member 27 is automatically elevated to clear the keeper whenever the disconnect handle is moved to the fully lowered Off position. This movement of the latch member may be effected by a step 49 on cam 40, which engages the under edge 50 of the latch member to move it about its pivotal mounting screw 47 fixed in the opening 51, Fig. 4. Movement of the latch member to the inoperative or release position may be limited in any suitable manner, as by reason of the latch member striking an abutment 46, Fig. 5, for example. It should be noted that movement of disconnect handle 12 to the Trip position does not move the cam 40 sufiiciently to lift the latch member out of engagement with keeper 26. Moreover, when the disconnect handle is in the Trip position, it covers the latch operating screw 47 as will be evident from a study of Fig. 1, thereby to preclude manipulation of the latch member from outside the cabinet unless the handle is advanced further toward Oif position.

Attention is now directed to the socket unit or plate 53 of Fig. 6, shown also in Fig. 5, which is designed to accommodate and move the circuit breaker actuator stud 14 whenever the cabinet door is closed. The socket unit plate may be provided with elongate slots 54- at its opposite. ends, receptive of screws 55 whereby the plate may be fixed in vertically adjusted positions flatwise upon the shifter plate 31. Atop the plate 53 may be fixed a pair of convergent arms 56 and 57 having free ends 58 spaced apart sufficiently to receive between them the circuit breaker actuator stud 14, Fig. 6. The arms 56 and 57 by preference are of resilient metal, so that they may be flexed toward and from plate 53, and will therefore accommodate themselves to the face of breaker housing 13 when advanced thereto by closing of the cabinet door. The arms may be fixed to plate 53 by means of rivets 64) or other suitable fasteners. A notch '61 in one edge of the plate provides clearance permitting lengthwise adjustment at 55 without interference with pin 41. The socket plate moves bodily with shifter plate 31, and will therefore move the circuit breaker actuator 14 lengthwise of slot 15 to closed and open circuit positions as the handle or lever 12 is manipulated, so long as the cabinet door is closed to place the arms 56-57 in embracing relationship to actuator 14.

Figs. 1, 3 and illustrate a key-operated lock 63 secured by screws or other fasteners 64 to the back of door 9, in position to place its bolt 65 in intercepting relationship to the upper edge 67 of shifter plate 31 when the bolt is extended. The location of bolt 65 should be such as to stop the shifter plate in its upward travel, before the socket unit 53 moves the circuit breaker actuator 14 to closed-circuit position. By preference, the lock bolt is so located as to stop the shifter plate at the Trip position of the disconnect handle 12, at which position the latch screw 47 is covered by said handle.

From the foregoing, it will be understood that an electrician having occasion to repair or alter electrical devices remote from the breaker 13, may move the disconnect handle to Trip or Off position to open-circuit the breaker, and then use a key to be kept in his possession, for extending the lock bolt 65 as in Fig. 5, thereby to preclude subsequent movement of the disconnect han dle 12 to the On position by persons unauthorized. Accordingly, the electrician is assured that the circuit breaker will not be closed by other persons to energize the circuit while he is working with equipment included in that circuit. Until the lock 63 is unlocked by means of the proper key, the circuit controlled by breaker 13 will necessarily remain de-energized, in the interest of safety to the electrician or technician in possession of the key.

In a slight modification of the structure, the lock may be of the type illustrated by Fig. 7, wherein the bolt 68 is spring-extended normally, but retractable by means of a proper key inserted in the keyhole 69. When the springprojected key-retracted bolt type of lock is used, the bolt will yieldingly bear against the side edge 70 of the shifter plate 31 when elevated, substantially as suggested by the disclosure of Fig. 3, until such time as the plate 31 is lowered by swinging the disconnect handle to Trip or Off position, when the resultant lowering of plate 31 will free the lock bolt for instant projection by means of the spring 71. The spring bolt so projected will overhang the top edge 67 of the shifter plate, as in Fig. 5, to preclude restoration of the closed-circuit condition of the breaker until such time as a proper key is used for retracting the bolt.

From the foregoing it will be at once apparent that the device as herein disclosed eliminates the hazard of unauthorized persons throwing the operating handle or lever 12 to closed-circuit position at a time when others are working on the circuit, thereby to enhance the safety factor of the installation. The application of locks as illustrated by Figs. 1, 3, 5 and 7, is accomplished with ease and dispatch, and with a minimum of labor and materials expense. The locks may be applied to existing circuit controllers as well as to new ones in process of manufacture, and various other advantages of the invention will become manifest to persons conversant with the art.

In conclusion, it may be pointed out that the Trip position of the disconnect handle is one which is assumed by the handle whenever the circuit breaker trips to automatically open the circuit due to overload or other circuit disturbances. Aside from the fact that the means of the invention may lock the handle against movement to the On position subsequently to automatic tripping, details of the trip mechanism itself are foreign to the present invention and need not therefore be disclosed herein.

It is to be understood that the key-operated lock bolt might be applied to intercept the shifter plate at other locations than that specifically shown on the drawings, or it might appropriately be applied to act upon other correspondingly movable parts of the device, if desired. Various other modifications and changes in the structural details of the device may be resorted to, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed is: 1

l. An electric circuit controller comprising in combination, a cabinet having side Walls and a door hinged to one of said walls for opening and closing movements, control means within the cabinet including a circuit breaker having a forwardly extending actuator stud movable substantially linearly to closed and open circuit positions, a shifter plate, means on the inner face of the door supporting the shifter plate for reciprocation in the direction of movement of the circuit breaker actuator stud, a socket member fixed to the shifter plate and receptive of said stud when the door is closed, means including a handle accessible exteriorly of the door for reciprocating the shifter plate, the socket member, and the actuator stud associated therewith, and a key-operated lock at the inner face of the door, including a bolt and a keyhole, the key-hole being accessible exteriorly of the door, and the bolt being located interiorly of the door in position to intercept the shifter plate in moving the circuit breaker stud from the open-circuit position toward the closedcircnit position.

2. The device as set forth in claim 1, wherein the combination includes a latch on the door and a cooperative keeper on the cabinet, and means associated with the handle to disassociate the latch from the keeper upon movement of the handle to open-circuit the breaker at the actuator stud.

3. An electric circuit controller comprising in combination, a cabinet having side walls and a door hinged to one of said walls for opening and closing movements, control means within the cabinet including a circuit breaker having an actuator movable substantially linearly to closed and open circuit positions, a reciprocable member carried by the door and including means engageable with the actuator when the door is closed, for transmitting movements to said actuator, means on the inner face of the door for supporting the reciprocahle member for movement in substantial correspondency with movements of the actuator to and from circuit closing position, a key-operated lock on the door, including a bolt and a keyhole, the keyhole being accessible exteriorly of the door, and the bolt of the lock being in position to limit reciprocatory movements of the reciprocable member upon extension of the bolt.

4. The electric circuit controller as set forth in claim 3, wherein the combination includes a movable handle mounted on the door exteriorly thereof, and means for transmitting movements of the handle to the reciprocable member aforesaid.

5. The electric circuit controller as set forth in claim 3, wherein the combination includes a movable handle mounted on the door exteriorly thereof, means for transmitting movements of the handle to the reciprocable member, a latch on the door, and a cooperative keeper on the cabinet, and means associated with the handle to disassociate the latch from the keeper upon movement of the handle to open-circuit the breaker at the actuator.

6. An electric circuit controller comprising in combination, a cabinet having side walls and a door hinged to one of said walls for opening and closing movements, control means within the cabinet including a circuit breaker having a forwardly extending actuator stud movable substantially linearly to closed and open circuit positions, a shifter plate including a socket engageable with the actuator stud when the door is closed, for transmitting movements of the shifter plate to said stud, means on the inner face of the door supporting the shifter plate for reciprocation in the direction of movement of the circuit breaker actuator stud, means including a handle mounted upon the door exteriorly thereof for reciprocating the shifter plate and the actuator stud connected thereto at the socket, and a key-operated lock at the inner face of the door, including a bolt and a keyhole, the keyhole being accessible exteriorly of the door, and the bolt being located interiorly of the door in position to intercept the shifter plate in moving the circuit breaker stud from the open-circuit position to the closed-circuit position.

7. The combination as set forth in claim 6, wherein 6 the lock bolt is of the spring-extended key-retracted variety.

8. The device as set forth in claim 6, wherein the lock bolt is of the spring-extended key-retracted variety, and the combination includes a latch on the door and a cooperative keeper on the cabinet, and means associated with the door handle to disassociate the latch from the keeper upon movement of the handle to an extreme position beyond the position required to open-circuit the breaker at the actuator stud.

9. An electric circuit controller comprising in combination, a cabinet having side walls and a door hinged to one of said walls for opening and closing movements, control means within the cabinet including a circuit breaker having a forwardly extending actuator stud movable substantially linearly to closed and open circuit positions, a shifter plate including a socket engageable with the actuator stud when the door is closed, for transmitting movements of the shifter plate to said stud, the shifter plate having an end and an intersecting side edge, means on the inner face of the door supporting the shifter plate for reciprocation in the direction of movement of the circuit breaker actuator stud, a key-operated lock on the door, including a key-retracted spring-extended bolt and a keyhole, the keyhole being accessible exteriorly of the door, and the bolt being located interiorly of the door in the path of movement of the shifter plate, the bolt normally riding upon the side edge of the shifter plate under the force of the bolt spring when the shifter plate is disposed at one limit of reciprocation, and adapted upon movement of the shifter plate to the opposite limit of reciprocation, to overlie the end of the shifter plate and thereby preclude return thereof to the original limit of reciprocation, until such time as the bolt is keyretracted.

10. The combination a set forth in claim 9, wherein the combination includes a shiftable handle mounted upon the door exteriorly thereof, and means associated with said handle for reciprocating the shifter plate and the actuator connected thereto at the socket.

11. An electric circuit controller comprising in combination, a cabinet having side walls and a door hinged to one of said walls for opening and closing movements, control means within the cabinet including a circuit breaker having a forwardly extending actuator stud movable substantially linearly to closed and open circuit positions, a shifter plate including a socket engageable with the actuator stud when the door is closed, for transmitting movements of the shifter plate to said stud, the shifter plate having a leading end advanceable upon movement of the shifter plate in a direction to place the circuit breaker actuator stud in the circuit-closing position, means on the inner face of the door supporting the shifter plate for reciprocation in the direction of movement of the circuit breaker actuator stud, a keyoperated lock on the door, including a bolt and a keyhole, the keyhole being accessible exteriorly of the door, and the bolt being located interiorly of the door in the path of movement of the leading end of the shifter plate upon extension of the bolt, for precluding disposition of the shifter plate and the circuit breaker actuator stud to circuit-closing position.

12. The electric circuit controller as set forth in claim 11, wherein the combination includes a shiftable handle mounted upon the door exteriorly thereof, and means associated with said handle for reciprocating the shifter plate and the actuator connected thereto at the socket.

References Cited in the file of this patent UNITED STATES PATENTS 2,550,125 Schueler et a1. Apr. 24, 1951 2,645,688 DeSmidt et al. July 14, 1953 2,770,688 Johnson Nov. 13, 1956 

